Exam 4

Question 1

Actual tissue damage/injury that impairs host function

Answer 1

disease

Question 2

microbial parasite that causes disease, or tissue damage in host

Answer 2

pathogen

Question 3

the ability of a parasite to inflict damage on the host- measured in virulence (differs from host-to-host)

Answer 3

pathogenicity

Question 4

what pathogen is on

Answer 4

fomite

Question 5

how does the bacteria adhere and infect the cells?

Answer 5

-exposure to fomite
-bacteria/virus adheres to cell
-invasion (virulence factors allow virus to infect)
-multiply and colonize; start producing toxins and enzyme that cause illness
-no toxins unless population is large enough (quorum sensing)
-adhesin- glyco- lypoprotein molecule on outer part of cell allows for adhesion to our cells(usually epithelial cells first)

Question 6

Capsules

Answer 6

-part of adhesion(sticky, helps to stick to cell/eachother to form biofilms)
–not all have capsules
-thick slime layer on cell
-known as a virulence factor- help bacteria evade immune response

ex. of bacteria that have capsules:
Strep. pneumoniae

Question 7

Frederick Griffith

Answer 7

-proved that the capsule was the virulence factor
-discovered transformation

Question 8

What else do bacteria use for adherence?

Answer 8

fimbrae, pili, and flagella
-fimbrae- med.
-pili- short, hair like
-flagella (motility) but also help adhere

Question 9

Dental caries (strep sobrinus and strep mutans)

Answer 9

-saliva= defense mechanism (lysozomes), wash out bacteria, prevent adhesion
-some bacteria use saliva to adhere
-strep sobrinus attaches to mucus and saliva
-strep mutans (attach to teeth and gums)

-once mouth is colonized, lactic acid fermentation, use sucrose that is eaten as nutrient source.
-glycolysis then lactic acid fermentation, causes plaque that decay teeth

Question 10

invasiveness

Answer 10

ability to grow

Question 11

tropism

Answer 11

ability for bacteria to target certain tissue
-strep pneumonia tropism is lungs; swallow=dies, inhale=invasion

Question 12

bacteremia

Answer 12

bacteria is in blood but not actually colonizing blood; no replication. no replication, no colonizing, no producing toxins

Question 13

septicemia

Answer 13

bacteria colonizing blood, reproducing, producing toxins
septic shock and death

Question 14

virulence

Answer 14

ability to cause disease

Question 15

virulence factors

Answer 15

anything that give bacteria/virus advantage (capsules, toxins, enzymes, etc.)
-many have several factors

Question 16

What is LD-50?

Answer 16

measures virulence factors
-# of pathogens required to kill 50% of the animals in test group
-lower #= worse (doesn’t take a lot to kill population)
-high virulence- certain flu strains, ebola, strep pneumoniae

Question 17

attenuation

Answer 17

-where bacteria/virus loses its virulence factor
-kept in lab for long time- no need for bacteria to produce virulence factors= becomes attenuated

Question 18

How is attenuation beneficial?

Answer 18

used in vaccines.
-use attenuated strain, body forms immune response
-put into chicken eggs, colonize, extracted for vaccine- live attenuated vaccine- we produce memory cells- immune respones= works the best but can be dangerous for immune deficient ppl- get sick or can revert back to virulence
-some attenuated use dead virus

Question 19

What is a compromised host? What kinds of people are compromised?

Answer 19

-don’t have good immune response= opportunistic pathogens, get very sick
-HIV/AIDS pts, cancer pts, elderly, ppl who take a lot of antibiotics
-get nosocomial infections (healthcare associated infections) like MRSA, C. Dif.

Question 20

Tissue-destroying enzymes

Answer 20

-virulence factors
-enzymes usually exoenzymes(sent out by bacteria)

Question 21

Hyalurondase enzyme

Answer 21

-breaks down hyaluronic acid in skin/tissues
(strep, staph, and clostridia cause boils (pyogenese= “pus forming”

Question 22

Collagenase enzyme

Answer 22

enzyme breaks down collagen
(clostridia perferengin- gangrene)

Question 23

Coagulase enzyme

Answer 23

enzyme that makes blood clot (strep aureus, only pathogenic strains produce coagulase)
-once infected in skin, produces coagulase- forms clot around bacteria- use as a barrier from macrophages- localized in boils)

Question 24

Streptokinase enzymes

Answer 24

-prevents blood from clotting, breaks down fibrin; immune response- clot in area to prevent bacteria from spreading- strep pyogenese

Question 25

What is an exotoxin?